Working tungsten.



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unrrnn STATES PATENT OFFICE.

.CARL T. FULLER, OF

EST ORANGE, NEW J EESEY, ASSIGNOR 'IO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK. I

WORKING TUNGSTEN.

No Drawing.

To all whom it may concern:

Be it known that I, CARL T. FULLER, a

citizen of the United States, residing at working by removing the skin .or surface.

portion in any suitable manner. The swaging or drawing may then proceed. The surface may be removed either chemically or mechanically. For example, the rod or wire may be dipped into or passed throu h a fusion of an oxidizing salt, such as used potassium nitrite, KNOQ, ipotassium nitrate- KNO sodium carbonate Na CQ, or barium chlorid. The length of time of the treatment will depend upon the condition of the tungsten rod, ordinarily a few seconds immersion in the fused salt is suflicient. Ac-

Specification of Letters Patent.

Patented Nov. 4, 1913 Application filed March 29, 1912. Serial No. 687,228.

cording to another method the outer layers of the metal are removed by making the' tungsten body the anode in a suitable electrolyte such as a 30% solution of potassium hydroxid, the cathode consisting ofcopper. The current strength, of course, may be regulated to remove the metal rapidly. The metal may also be removed mechanically as by grinding off the? hard layer with an emery wheel. After removing the outer layer or surface of metal by any of these methods the drawing, swaging, or other working process is continued.

What I claim as new and desire to secure by Letters Patent of the United States, is

l. The process of working metal which has become-brittle during drawing or other In witness whereof, .I have hereunto set my hand this 25th day of March, 1912.

CARL T. FULLER. Witnesses:

S. N. WHITEHEAD, .J. H. ELKINS. 

